I'll probably use a google sheet with a row for each prospect, and columns for spoke to, hotness (degree of suitability for my SaaS), and 'notes' (will put a new bullet point with brief summary of each call).
I was thinking it would be cool to record the calls and feed them to AI for some simple/crude auto-summary which automatically pulls out rejection reason, concerns, interesting points etc.
I might even vibe-code something myself, since I prefer primitive and reduced clutter. May open source it if I do. However, I'd be surprised if something like this doesn't already exist..